It is known to drive various automobile accessory assemblies, for example a water pump, generator, fan for cooling coolant, power steering pump, and compressor, using the vehicle engine. This is done by a driving pulley actuated by an engine shaft of the motor vehicle which drives an endless drive belt operating the accessory assemblies through driven pulleys.
Periodic torque pulses, for example, as may be initiated by combustion engine firing can create significant speed transitions which can interrupt smooth operation of the driven components. There may also be inertial and driven speed transitions associated with startup, shutdown, jake braking, gear shifting, etc. These transitions can result in undesirable effects such as belt jump, belt wear, bearing wear, noise, etc.